The present disclosure relates to a tantalum capacitor and a method of manufacturing the same.
Tantalum (Ta) is a material widely used throughout various industrial sectors, such as in the aerospace industry and in the defense sector, as well as in the electrical, electronic, mechanical, and chemical fields, due to desirable mechanical and physical properties such as a high melting point, excellent flexibility, excellent corrosion-resistance, and the like.
Since tantalum can form a stable anodic oxide film, tantalum has been widely used as a material for positive electrodes of small capacitors. Recently, in accordance with the rapid development of information technology (IT), information and communications technology (ICT) and electronics technology, the use of tantalum has been increasing every year.
Generally, a capacitor is a condenser temporarily storing electricity therein, and includes two flat plate electrodes, which are disposed in close proximity to each other, and insulated from each other when a dielectric substance is inserted therebetween. The two plate electrodes may be charged with electric charges due to attractive force, thereby allowing electricity to be accumulated therein. Such a capacitor stores electric charges and electric fields in a space enclosed by two conductors, and is commonly used to acquire capacitance.
A tantalum capacitor containing a tantalum material has a structure in which voids are formed at the time of sintering and curing tantalum powder, and is completed by forming tantalum oxide (Ta2O5) on a tantalum surface using an anodic oxidation method, forming a manganese dioxide (MnO2) layer, an electrolyte, on the tantalum oxide layer acting as a dielectric substance, forming a carbon layer and a metal layer on the manganese dioxide layer to form a body, forming positive and negative electrodes on the body for being mounted on a circuit board, and forming a molded part.
Since a tantalum capacitor according to the related art has a structure in which a board layer is formed on an electrode connection portion in order to connect a tantalum material and an electrode to each other, and a connection path such as a via hole is formed in the board layer, an internal space of a molded part may be relatively small, such that it may be difficult to increase efficiency of a capacitor body or achieve a wide range of design freedom in terms of positive and negative electrodes.
Therefore, a structure in which an internal lead frame is used, or a terminal is exposed to the outside without a frame has been introduced.
In the case of the structure using the internal lead frame, a space occupied by tantalum material in the molded part is decreased by the internal lead frames configuring the positive and negative electrodes, and since capacitance is in proportion to a volume of the tantalum material, capacitance may be limited correspondingly.
In the case of the structure in which the terminal is exposed to the outside without the frame, since a plurality of contact materials are present, contact resistance may be increased by the plurality of contact materials, such that equivalent series resistance (ESR) and equivalent serial inductance (ESL) of the capacitor may be increased.
Further, in the case of such a structure in which the terminal is exposed to the outside without the frame, since a negative electrode lead is positioned on a side of a product, a welding distance for forming a solder should be secured between the tantalum material and the negative electrode lead, such that an internal volume of the tantalum material may be decreased. Therefore, capacitance may be decreased.